Encapsulated curcumin results in prolonged curcumin activity in vitro and radical scavenging activity ex vivo on skin after UVB-irradiation.

The phytochemical curcumin possesses antioxidant activity; however, it becomes unstable after being exposed to light or heat or loses activity during storage. This is especially important when curcumin is applied to the skin within a cosmetic or pharmaceutical formulation, since sun exposure is unavoidable. This drawback can be directly addressed by encapsulation of curcumin in photo-stable nanospheres. Therefore, curcumin was encapsulated into nanoparticles consisting of ethyl cellulose and/or methyl cellulose. Nanoparticles were subjected to processing conditions commonly used in industry, for example, temperature and pressure and thus retained their morphology. Furthermore, sun exposure resulted in the protection of curcumin by nanoparticles, whereas non-encapsulated curcumin degraded completely. Determination of the radical protection factor resulted in similar antioxidant activity of encapsulated and non-encapsulated curcumin indicating that curcumin maintains its antioxidant activity. Application of lotions containing curcumin or curcumin nanoparticles to the skin and subsequent UVB-irradiation resulted in less radical formation compared to lotion application only. Moreover, radical formation was even less after nanoparticle application compared to free curcumin. Nanoencapsulation protects curcumin from photo degradation and can therefore prolong the antioxidant activity of curcumin.

Effects of drying temperature and surface characteristics of vegetable on the survival of salmonella.

The heat resistance of Salmonella Anatum inoculated on the surface of a model vegetable as affected by hot-air drying temperature (50 to 70 degrees C) and surface characteristics was determined in this study. Cabbage was selected as a model vegetable to demonstrate the effect of topographical feature of vegetable surface on the Salmonella attachment ability. An image analysis technique was developed to monitor the change of cabbage surface during drying and the specific surface characteristics were described in terms of the roughness factor (R). It was found that the water activity of the vegetable decreased while R-value increased with longer drying time and higher drying temperature. However, the changes of both parameters during drying did not show a significant effect on the susceptibility of Salmonella attached on the cabbage surface. Drying temperature was found to be a major factor influencing the heat resistance of Salmonella during drying.

Quality changes of shrimp during boiling in salt solution.

Boiling shrimp in salt solution is an important step during the production of dried shrimp. In this study the effects of various boiling parameters, namely, concentration of salt solution (2, 3, and 4% w/v), mass ratio of shrimp to salt solution (1:2 and 1:3), boiling time (1, 3, 5, and 7 min), and shrimp size (small and large), on the various quality attributes of shrimp were investigated. The quality of boiled shrimp was evaluated in terms of its salt content, moisture content, which is in turn related to the other qualities, namely, protein content, colors, shrinkage, and texture (hardness and toughness), as well as microbiological quality. It was found that higher concentration of salt solution and longer boiling time and lower mass ratio of shrimp to salt solution led to higher salt content of shrimp but to lower levels of moisture and proteins, leading to higher values of hardness, toughness, shrinkage, and color changes of shrimp. However, the mass ratio of shrimp to salt solution alone did not significantly affect any qualities of boiled shrimp (P > 0.05). It was found that the minimum boiling time of 3 min was enough to reduce the number of microorganisms to a safe level and inactivate enzymes causing melanosis in boiled shrimp.

Effects of process parameters on quality changes of shrimp during drying in a jet-spouted bed dryer.

The objective of the present study was to investigate the effects of various parameters, that is, concentration of salt solution (2%, 3%, 4%[w/v]), boiling time (3, 5, 7 min), drying air temperature (80, 100, 120 degrees C), and size of shrimp, on the kinetics of drying and various quality attributes of shrimp, namely, shrinkage, rehydration ability, texture, colors, and microstructure, during drying in a jet-spouted bed dryer. In addition, the effects of these processing parameters on the sensory attributes of dried shrimp were also investigated. Small shrimp (350 to 360 shrimp/kg) and large shrimp (150 to 160 shrimp/kg) were boiled and then dried until their moisture content was around 25% (d.b.). It was found that the degree of color changes, toughness, and shrinkage of shrimp increased while the rehydration ability decreased with an increase in the concentration of salt solution and boiling time. Size of shrimp and drying temperature significantly affected all quality attributes of dried shrimp. The conditions that gave the highest hedonic scores of sensory evaluation for small dried shrimp are the concentration of salt solution of 2% (w/v), boiling time of 7 min, and drying air temperature of 120 degrees C. On the other hand, the conditions that gave the highest hedonic scores of sensory evaluation for large dried shrimp are the concentration of salt solution of 4% (w/v), boiling time of 7 min, and drying air temperature of 100 degrees C. The quality attributes of dried shrimp measured by instruments correlated well with the sensory attributes, especially the color of dried shrimp.